body {
    font-family: 'Arial', sans-serif;
    background-color: #f4f4f9;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-image: linear-gradient(135deg, #f4f4f9, #e0e0e0);
    /* 添加背景动画效果 */
    background-size: 400% 400%;
    animation: gradientBackground 15s ease infinite;
}

@keyframes gradientBackground {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.container {
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    width: 350px;
    text-align: center;
    transition: transform 0.3s ease;
    /* 添加容器动画效果 */
    animation: fadeIn 1s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

.container h2 {
    margin-bottom: 25px;
    color: #333;
}

.container input[type="text"],
.container input[type="password"] {
    width: 100%;
    padding: 15px;
    margin: 10px 0;
    border: 1px solid #ccc;
    border-radius: 5px;
    transition: border-color 0.3s ease;
}

.container input[type="text"]:focus,
.container input[type="password"]:focus {
    border-color: #007bff;
    outline: none;
}

.container button {
    width: 100%;
    padding: 15px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.container button:hover {
    background-color: #0056b3;
}

.toggle-form {
    margin-top: 20px;
    color: #007bff;
    cursor: pointer;
    transition: color 0.3s ease;
    /* 添加切换表单动画效果 */
    animation: fadeIn 1s ease-in-out;
}

.toggle-form:hover {
    color: #0056b3;
}

/* Additional Enhancements */
.container::before {
    content: '';
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 20px solid transparent;
    border-right: 20px solid transparent;
    border-bottom: 20px solid #fff;
    z-index: -1;
}
.method-btn {
    margin: 5px;
    padding: 10px 20px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.method-btn:hover {
    background-color: #0056b3;
}

.form {
    margin-top: 20px;
}
.container::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 20px solid transparent;
    border-right: 20px solid transparent;
    border-top: 20px solid #fff;
    z-index: -1;
}